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New KT150 tubes?

Has anyone any experience with these pretty new tubes. There are already one or 2 amps I know of, that use them. The review of one of these amps in a UK magazine suggested they were a little warmer and more natural sounding than the nearly new KT120's

The article also suggested they were a straight swap for KT120 based amps, with no adjustment necessary. They are more than twice the cost of KT120's, but still not too costly compared with NOS tubes. I know changing from KT88's or 90's to 120's. did require some amp modification. I have an ARC reference 75 and might want to try the new tubes at some point, ARC don't seem to have a customer E-mail service, to ask the question
david12
wolf_garcia
4,650 posts
 
My KT120s must have more than 3000 hours on them by now, and no signs of drifting bias or sonic issues yet...they still sound strong.
knghifi
1,667 posts
 
10-28-13: Booboobaer
Actually Xtil6 I have about 200 hours and they are still opening up.I have been told by Paul Weitzel that I should give them at least 500 hours to start seing what they can do. This is not unreasonable since I saw the same results with the KT 120.
1/4 of expected life just for break-in? OK, got a 10000 shares long market order on TS. LOL!
wolf_garcia
4,650 posts
 
Yeah...after 3000 plus hours I think these are starting to break in...by next June they should be gettin' real good.
hifigeek1
770 posts
 
Regarding the KT-150. It is not known yet if this tube is a drop in replacement for the KT-120. I'm awaiting info from the ARC engineering dept. on this issue. The KT-150 puts out more power than the KT-120 which could mean it draws more heater current than the KT-120 does. When I get more info on this, I will share it here. Until that time, I would be very careful using this tube.
joe_appierto
81 posts
 
According to the New Sensor data sheet on the KT150, the heater current is not less than 1.75A and not more than 2.0A and for the KT 120 it's not less than 1.7A and not more than 1.95A. So, they're pretty close in that regard.

There may be other characteristics, physical, mechanical or electrical that may preclude using the KT150 in applications that are designed for the KT120. Physical size is an obvious one.
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